Council mulls pluses, minuses of water treatment options
The Portland City Council is between a rock and a hard place when it comes to treating a potentially deadly parasite in the Bull Run Watershed. They can either spend $105 million to prevent a problem that has not yet surfaced — or up to $500 million to also prevent additional problems that don't yet exist.
The public has a chance to weigh in this coming Tuesday at the first public hearing on what to do about the cryptosporidium that was repeatedly found there earlier this year.
A reservoir in the watershed is the primary source of water for Portland and many suburban communities. Although drinking Bull Run water never has been proven to make anyone sick, the U.S. Environmental Protection Agency is now requiring the city to treat the drinking water for the cryptosporidium parasite.
As Portland Water Bureau officials explained to the City Council at a work session last Tuesday, one option is spending $105 million on an ultraviolet treatment plant that only kills the parasite. Another option is spending between $300 million and $500 million on a filtration plant that also would solve a number of potential future problems.
Or the city could commit to spending over $600 million and do both.
All options likely will raise water rates. Although estimates are not yet available, council members were clearly uncomfortable with any increase last week, because the Water Bureau already is committed to completing a number of other costly projects. Those include replacing the open reservoir in Washington Park with an underground storage tank and building a large earthquake-proof water pipe across the Willamette River to guarantee service to westside customers after a natural or manmade disaster.
The council must make its decision by Aug. 11, just a little over a month from now.
Forcing the city's hand
Last week's work session was scheduled after the Oregon Health Authority announced it will revoke the city's variance from EPA rules requiring treatment for crypto — as the parasite is commonly called — on Sept. 22. Portland owns and operates the only large municipal water system in the country that does not currently treat for it.
The city received a variance from the health authority in 2012 because Bull Run water historically has been so clean. But the variance required the bureau to test for crypto and report its findings. No traces of crypto were found until this year, when 14 samples tested positive between January and March, exceeding the allowable level in the variance. The variance revocation was announced on May 19.
Water Bureau Director Michael Stuhr made his preference clear at last week's work session.
"If I was made of money, I would build a filtration plant and I wouldn't think twice about it. It does so many things," he said.
But that option could cost between $300 million and $500 million.
As Stuhr explained it, a filtration plant will remove all contaminants from the water, not just crypto. That includes anything else the EPA might ban in the future. It also includes ashes from wildfires and mud deposited in the reservoir by earthquakes and large landslides in the watershed.
Stuhr characterized both possibilities as low-probability, high-risk "Black Swan" events that water professionals should plan for. Although much more rain falls in the watershed than in Portland, it could become drier and more prone to fire in the summer because of climate change.
Of the 76 surface-water suppliers in the United States that provide more than 100 million gallons per day, 71 use filtration plants to meet EPA requirements, including the Clackamas River Water utility district and the Willamette River Treatment Plant serving Wilsonville. All but the one in Tacoma, Washington, were built before the crypto rule was adopted. Only five providers operate UV plants.
On the other hand, not only does a filtration plant cost more to build than a UV plant, it also costs more to operate every year. While a UV plant would cost $2.5 million year, a filtration plant could cost $4 million to $5.5 million, in large part because of the energy required to push water through sand or a membrane.
And a filtration plant would take longer to build. The bureau has done a lot of preliminary work on a UV plant. It could be completed in five years. A filtration plant would have to be planned from scratch and could take 10 years or more to complete.
"Obviously there is a cost-benefit trade-off here," said Mayor Ted Wheeler, who asked for a more detailed analysis of the potential risks of either decision.
Option to build both
Wheeler and Commissioner Amanda Fritz also asked whether a UV plant could be built now and a filtration plant be built later. Stuhr said yes, noting that aging components of the UV plant would have to be replaced at great expense in about 25 years. The council could instead build it and set money aside every year for construction of a filtration plant that would be ready to come on line then, he noted.
Most of Portland's suburban customers prefer the city build a filtration plant, says Mark Knudson, CEO of the Tualatin Valley Water District. Knudson says the additional benefits — including allowing more water to be drawn from the Bull Run Reservoir every summer — outweigh the higher cost and longer construction time.
"This is a unique opportunity to move forward on a comprehensive solution to the region's water needs that includes filtration," says Knudson, who was at the work session but not invited to testify.
Crypto is transmitted through animal feces. It can cause cryptosporidiosis, a respiratory and gastrointestinal illness, which killed 104 people and sickened thousands of others in 1993 in Milwaukee, Wisconsin. That outbreak prompted the EPA to adopt its treatment rule.
Only a few strains of crypto are dangerous to people, mostly those in human and cattle feces. None has been found in the watershed, which is closed to people and farm animals. But the EPA rules do not distinguish between the different strains, Stuhr said.
The council has scheduled a hearing on Aug. 2 to take public testimony and make a decision.
Before that, the public can testify on the options before the Portland Utility Board, a citizen advisory group to both the water and sewer bureaus. It will meet from 4:30 p.m. to 6 p.m. on Juy 11 in Room C of the Portland Building, 1120 S.W. Fifth Ave.
The PUB will meet again the next week to make a recommendation to the council.